A growing number of television content sources enable interactive television. When operational, interactive television provides useful e-commerce, advertising, and information capabilities to viewers. One mechanism for interactivity typically involves the insertion of information or data in hidden portions of a television video signal. This information can range from a simple web link, such as an Internet uniform resource locator (URL) address, to a fairly complete set of extensible markup language (XML) information that can form a complex web page accompanied by web links (e.g., to advertisers' web pages). Advanced Television Enhancement Forum (ATVEF) triggers or triggering techniques by Wink are examples of mechanisms for providing interactive information along with television signals.
This information (e.g., triggers and accompanying content and data, which will be referred to collectively herein as “trigger information”) is typically inserted or carried in a vertical blanking interval (VBI) portion of an analog television video signal. For digital television broadcasts, this trigger information may be inserted into a special data slice of an MPEG-2 bit stream or signal. Modern analog/digital set top boxes or other client terminals can decode these signals to obtain the trigger information, and with the appropriate enabling software, convert the trigger information into a rich interactive experience for the viewer.
Unfortunately, typical television systems leave the interactive experience under the exclusive control of content providers. The cable service provider or multiple system operator (MSO) has limited opportunity to customize or enhance that experience for the viewer. In other words, because the content providers are typically the parties that provide and insert the trigger information into the television signals, the MSO's role is often reduced to simply relaying the television signals to viewers without any modification or customization.
An area where this limitation can cause problems is in television advertising. Because the content providers generally provide the television signals having the embedded triggers (which correspond to advertisements present in the television signal), current techniques for advertisement substitution (or “advertisement swapping”) may be difficult to implement, due to the technical differences between interactive television and conventional television and due to many MSOs' limited capability to modify television content provided from content providers. For example, simply swapping a national commercial with a local commercial (so that specific local retail merchant information can be provided to the viewer, for instance) is more easily said than done in an interactive television environment, given factors such as ensuring that URL addresses are consistent and correct, the capabilities of subscribers' terminals to recognize and process interactive content, licensing considerations, and so on.
Accordingly, improvements are needed in techniques for providing advertisements to interactive television viewers.